Muscle strength testing with one repetition maximum in the arm/shoulder for people aged 75+-: test-retest reliability

Objective: To investigate the reliability of a muscle strength test of the arm/shoulder in elderly people, aged 75 and older, and to compare subjects with and without previous muscle strength training experience. Design: Reliability study - test-retest. Setting: Research centre for the elderly. Main measures: One repetition maximum (1 RM) was measured using an arm/shoulder strength-training device (Pull Down, Norway). Two measurements were conducted, approximately one week apart. Results: Forty people were included in the study and 34 completed both sessions. Eleven participants had previous muscle strength training experience on the indicated device. There was a high correlation between the test sessions, r = 0.97 for both groups. The analysis of 95% limits of agreement for the mean difference was -4.3/+6.9 kg for the group without and -3.0/+6.4 kg for the group with previous experience, respectively. Conclusion: One repetition maximum evaluated by the Pull Down device seems to be a reliable and safe method for dosing and evaluating a muscle strength training programme for elderly people. The observed variation of approximately -4/+7 kg cannot be interpreted as an effect of muscle training, but is more likely an effect of learning, fluctuations in daily condition and/or motivation.